In supermarkets and retail stores, floor fixtures such as freezer and refrigerator cases, floor shelving, and product displays, are susceptible to damage due to collisions with shopping carts, floor scrubbers, pallet jacks, stock carts, and the like. For example, freezer and refrigerator cases typically include a glass or transparent plastic door for viewing the product without opening the door. The glass can be shattered, or the plastic scratched, upon impact with shopping carts, or the like. Since the body of many of these floor fixtures is constructed of lightweight aluminum or hardened plastic, it can be easily dented or cracked by such impacts. Likewise, in industrial locations, including warehouses and manufacturing facilities, product storage, doorways, equipment, and the like, are susceptible to damage due to collisions with heavy equipment, such as delivery vehicles, forklifts, and the like.
A bollard protects objects from collisions with things from shopping carts to delivery vehicles or automobiles. Bollards are commonly employed inside a store to block shopping cart access to certain areas and outside a store to protect outdoor structures from collisions, to indicate parking areas, to block vehicle and heavy equipment access to a particular area, and to direct a flow of traffic. Bollards can also be used to block vehicular access for security reasons.
In part due to the diverse applications for bollards, the market has thusfar derived two primary types of bollards, namely, plate-mounted bollards and core-drilled bollards. Plate-mounted bollards conventionally involve a steel plate having three or four bolt holes and a bollard extending perpendicularly from one face of the plate. The plate sits on the floor and bolts are used to fasten the plate, and therefore the bollard, to the floor through the bolt holes. There is no significant disruption to the ground or floor, other than the bolt holes, which are in some instances pre-drilled. On the other hand, core-drilled bollards conventionally require a major disruption to the ground or floor with the creation of a hole 2-4 feet deep and having a larger diameter than the bollard itself (e.g., 8 inches to 2 feet, or larger). Concrete is poured into the hole and the bollard is placed in the concrete and held vertically while the concrete cures. In some instances, concrete is also poured into the hollow bollard itself Installation of a core-drilled bollard is significantly more expensive than with a plate-mounted bollard, and takes significantly more time to complete. However, there are locations where the core-drilled bollard is required due to its ability to absorb larger impacts than the plate-mounted bollard.
The plate-mounted bollards conventionally are utilized in areas where impacts are more likely to be less severe, and involve lighter objects, or where no significant impacts are likely and the bollard serves more as a marker. For example, inside a grocery store in front of a freezer case any impact would likely be from a shopping cart or floor polisher. Such an impact would be considered to be low-energy, or relatively minor. Accordingly, a plate-mounted bollard would be appropriate for this type of installation. Contrarily, in a warehouse with heavy equipment, such as delivery vehicles and forklifts, impacts are more likely to be more severe, or high-energy. A vehicle backing up may accidentally collide with a bollard. Accordingly, a core-drilled bollard would be more appropriate in these types of settings.
There are a substantial number of installations where a conventional plate-mounted bollard does not provide quite enough impact protection; however, a core-drilled bollard is significantly over-sized for the application. Yet, a core-drilled bollard is installed because the conventional plate-mounted bollard falls short of providing the required protection. Likewise, there are installations where a core-drilled bollard is necessary to provide protection against likely impacts, yet a plate-mounted bollard is installed because they are less expensive or there are logistical problems with drilling 4 foot deep holes for the core-drilled bollard installation. One of ordinary skill in the art will appreciate that there are other factors that may influence the selection of a plate-mounted bollard or a core-drilled bollard.
The ability of the conventional plate-mounted bollard to absorb impact energy is, to date, limited by the strength of the three or four bolts holding the plate and bollard in the ground. When a plate-mounted bollard experiences a collision with an object, the impact is absorbed primarily at the intersection between the bollard and the plate to which it is mounted.
Looking at FIG. 1, an example conventional bollard 10 coupled with a plate 12 and mounted to the ground with bolts 14 is illustrated. More specifically, a bollard 10 that is 36 inches high, for example, most often receives impact forces in the first 18 inches off the ground. This is because bumpers of equipment that most often collide with the bollards are typically in that height range. As the bollard receives an impact force (F1), the bollard 10 (which is typically rigid so as to avoid damage from collisions) acts as a lever or moment arm. Due to the rigidity of the bollard, the force (F1) is immediately experienced at an intersection (I) of the bollard 10 with the plate 12, which in turn pulls upward on the bolts 14 holding the plate 12 to the ground. Magnified levels of the impact force (F1) are experienced by the intersection (I) due to the moment arm phenomenon. The bolts 14 are also subject to forces sufficient in some instances to pull the bolts 14 out of the ground. There is no give, or flex, in these rigid plate-mounted bollards to absorb some of the impact forces.
Even with bollards that include some form of spring mechanism internally, if the bollard is mounted to the plate, the impact force (F1) is typically received at the intersection thereof without much absorption of the impact force anywhere else in the bollard structure. If, alternatively, the intersection between the base plate and the bollard is hinged or pivoted and has a spring holding the bollard upward, then such a structure is unable to withstand substantial impact forces without pivoting over on its side, resulting in excessive lateral movement at the upper end of the bollard (if the top of the bollard moves a lot on impact, it may collide with the nearby structure it is supposed to be protecting). Accordingly, in conventional plate-mounted bollards, the force immediately generates a lever scenario where the impact force that results is a greater impact force than can be absorbed by the bolts, the bolts may pull out of the floor, or altogether fracture, or the floor may buckle attempting to withstand the impact.
A core-drilled and cemented bollard withstands such impacts as described above because a greater length of sub-floor bollard and a substantial area of concrete hold the base of the bollard in place. When the ability to absorb a larger impact is required, the convention is to utilize a core-drilled bollard.
Example ranges of impact forces that are typically managed by conventional plate-mounted bollards include ranges of up to about 4000 lbs with maximum lateral movement at the top of the bollard of about 3 inches due to the limitations described above. Example ranges of impact forces that are generally managed by conventional core-drilled bollards include ranges of up to about 16,000 lbs, with no substantial lateral movement of the top of the bollard at impact, or with movement of less than about 1 inch. As can be seen, the core-drilled bollards can manage substantially greater impact forces, but they require significantly more expensive and time intensive installations.